The present invention relates to a composite material and to an apparatus and to a method for making such a composite material; and more particularly relates to such a composite material which is reinforced by fine powder particles which are themselves made up in a composite structure and includes extremely small ceramic particles in a matrix of metal, and to an apparatus and method for this type of composite material.
The present invention was originally made in Japan, and the first patent application made therefor was Japanese Patent Application No. 81535/83, of which priority is being claimed in the present application; and it is hereby desired to incorporate the subject matter of that previous Japanese patent application into this specification by reference; a copy is appended to this specification.
Ceramics such as alumina, silicon nitride, tungsten carbide, and so on are far superior in heat resistance and wear resistane to metals, and therefore there have been in the past various attempts to make various structural members of various machines and devices out of composite materials in which ceramic powder particles are dispersed within a matrix of metal, as well as composite materials in which matrix metal is reinforced by ceramic fibers.
The problems with such composite materials made with ceramic reinforcing powder particles in matrix metal are that the reinforcing powder particles are extremely brittle, that it is difficult to uniformly disperse the reinforcing particles in the matrix metal, and that the intimacy between the reinforcing particles and the matrix metal is not always very good. Because of these problems, such composite materials are not in practice used very much, except for some tool materials such as cermet.
The problem of brittleness of the reinforcing ceramic powder particles might be thought of to be solvable by using as reinforcing powder particles small particles which themselves had a composite structure, being made of still finer ceramic particles set within a matrix of metal; but although such a substance can be conceived of in theory there is no practical way in which such fine composite powder particles can be made with an average particle diameter of 10 microns or less, which is a smallness which is necessary for their use as reinforcing powder particles. Therefore, up to the present, it has not been possible to manufacture a composite material utilizing such composite reinforcing powder particles.